Md. Code, Environment § 9-1111

(a) In this section, “rural zone” means an area of Montgomery County designated as a Rural Zone, Rural Cluster Zone, Rural Density Transfer Zone, Rural Neighborhood Cluster Zone, or Rural Service Zone as described in the Montgomery County Code Zoning Ordinance.

(b) (1) Except as provided in subsection (c) of this section, in Montgomery County, an on–site sewage disposal system or well located in a rural zone may only serve one additional lot or parcel that has been subdivided from a single property on which the on–site sewage disposal system or well is located under an on–site sewage disposal system easement or well easement, respectively, provided that:

(i) The property on which the on–site sewage disposal system or well is located does not have an existing on–site sewage disposal system easement or well easement;

(ii) The subdivision of the property was made in accordance with a State or county agricultural land conservation program if the property is subject to an agricultural land conservation easement; and

(iii) Only one on–site sewage disposal system easement may serve only one subdivided lot or parcel.

(2) An easement for an on–site sewage disposal system or well under paragraph (1) of this subsection may be granted from the original parcel to a new lot or parcel being created and the easement must not be granted to any lot or parcel that did not originate from the same original parcel.

(c) An on–site sewage disposal system or well under subsection (b)(1) of this section may not:

(1) Serve land that is designated by the State or the governing body of Montgomery County as a special protection area; or

(2) Decrease the land available for agricultural production by more than 4,000 square feet.